[vtkusers] Memory problem (coloring >44000 tetrahedrons objects)

[Eugene Kim]

Hello,

  	Admittedly I did not read your entire report, but I am also having 
memory errors with vtkPoints.  Quite often, accessing data in vtkPoints 
results in a segfault.  Could more people confirm this?  I sent an email 
to this group a couple weeks ago about this and no one responded.

Thanks,
Eugene Kim

On Fri, 24 Mar 2006 ksm-pb at ipt.rwth-aachen.de wrote:

>
> Hello vtkusers mailing list,
>
> i ve a problem with the memory usage of my VTK application. I create more
> than 44000 tetrahedron objects which each have to have a different color
> and i hope someone can help here.
>
> The 44000 vtkTetra objects are no problem as long as i put all of them into
> the same vtkUnstructuredGrid object and using the same color for each
> tetrahedron like this:
>
> // iCons contains the indexes for the tetrahedron point connectivities
> int * const * iCons = GetCons();
> int iNumofPoints = GetNumOfPoints();
>
> vtkUnstructuredGrid * pUnsGrid = vtkUnstructuredGrid::New();
> vtkPoints * pPoints = vtkPoints::New();
>
> ... // Feeding pPoints from an external data format (10327 coords in my
> app)
>
> pUnsGrid->Allocate(iNumOfPoints, iNumOfPoints);
> pUnsGrid->SetPoints(pPoints);
>
> for (int i = 0; i < iNumOfTetra; ++i) {
>      vtkTetra * pTetra = vtkTetra::New();
>      vtkIdList * pTetraIdList = pTetra->GetPointIds();
>
>      for (int j = 0; j < 4; ++j)
>            pTetraIdList->SetId(j, iCons[j][i]-1); // iCons knows which IDs
> to set for each tetrahedron!
>
>      pUnsGrid->InsertNextCell(pTetra->GetCellType(), pTetraIdList);
> }
>
> vtkOpenGLActor * pActor = vtkOpenGLActor::New();
> vtkDataSetMapper * pMapper = vtkDataSetMapper::New();
> pActor->SetMapper(pMapper);
> pActor->GetProperty()->SetColor(1,0,0);
> pActor->SetScale(.1,.1,.1);
> pMapper->SetInput(pUnsGrid);
>
> This solution works okay with about 30MB of RAM usage, but each tetrahedron
> has the same color (1,0,0) now. BUT however if i want each tetrahedron to
> have a different color i would have to create for each 44000 tetrahedrons
> its own vtkUnstructuredGrid, vtkOpenGLActor and vtkDataSetMapper objects.
> So i got at least 44000 * 3 = 132000 more objects in the memory. This way
> the app would consume more than 2GB of RAM (and its swapping about 100MB)!
> Also the display speed with the vtkOpenGLRenderer gets very very slow! The
> code is like this:
>
> int i NumOfTetras = GetNumOfTetras();
> std::vector< vtkOpenGLActor* > vecActors;
> vecActors.resize(iNumOfTetras);
>
> for (int t = 0; t < iNumOfTetras; ++t )
>      vtkPoints * pPoints = GetTetraPoints(t);
>      vtkUnstructuredGrid * pUnsGrid = vtkUnstructuredGrid::New();
>
>      pUnsGrid->Allocate(4, 4);
>      pUnsGrid->SetPoints(pPoints);
>
>      vtkTetra * pTetra = vtkTetra::New();
>      vtkIdList * pTetraIdList = pTetra->GetPointIds();
>
>      for (int j = 0; j < 4; ++j)
>            pTetraIdList->SetId(j, j);
>
>      pUnsGrid->InsertNextCell(pTetra->GetCellType(), pTetraIdList);
>
>      vtkOpenGLActor * pActor = vtkOpenGLActor::New();
>      vtkDataSetMapper * pMapper = vtkDataSetMapper::New();
>      pActor->SetMapper(pMapper);
>      pActor->GetProperty()->SetColor(GetTetraColor(t));
>      pActor->SetScale(.1,.1,.1);
>      pMapper->SetInput(pUnsGrid);
>      vecActors[t] = pActor;
> }
>
> // Using vecActors to display all the tetrahedrons with different colors
> each!
>
> I have to find another way to enable different colors for each tetrahedron
> because its very importent to this application. The colors have to
> visualize the mesh's temperatures of a drilling simulation demo.
>
> Thanks for reading my problem, I am looking forward for some ideas how to
> solve this problem!
>
> Cheers,
>
> Paul Bütow
>
>
> -----------------------------------------------------------------
> Paul C. Buetow
> Fraunhofer Institut für
> Produktionstechnologie IPT
> Virtual Reality Labor
> Steinbachstraße 17
> 52074 Aachen
>
> E-Mail: paul.buetow at ipt.fraunhofer.de
> Internet: www.ipt.fraunhofer.de
>
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